Anthraquinonoid disperse dyes

The present invention relates to new anthraquinonoid disperse dyes based on 1,4-diamino-nitro-hydroxyanthraquinone.

The new dyes have the formula ##STR3## where X is chlorine or bromine and Y is ##STR4## and n is 0, 1, or 2.

The dyes color synthetic textile materials, especially consisting of polyester, nylon and cellulose acetate fibers, in clear blue hues. The dyes are very fast to thermofixing, washing and light.

The dyes (I), in the pure form or, preferably in the form of mixtures containing the various dyes of the formula (I), may be used for dyeing synthetic fibrous materials. Mixtures of compounds (I) in which n is 0 and 1 and X is bromine are particularly preferred. Of these mixtures, those containing from 5 to 12% by weight of bromine are, in turn, preferred.

Dye mixtures of compounds (I), where Y is ##STR5## X is Br and n is 0 and 1, which contain from 5 to 12% by weight of bromine, are very particularly preferred.

The dyes of the formula I with n = 0 can be manufactured by condensing 1-amino-8-nitro-4,5-dihydroxyanthraquinone with amines Y-NH 2 in the presence of boric acid in accordance with the process described in British Pat. No. 1,284,932.

The condensation is advantageously carried out by introducing the boric acid into phenol, distilling off the water, then adding the amino-nitro-dihydroxy-anthraquinone and the amine Y-NH 2 and thereafter heating the reaction mixture, advantageously at from 60° to 110° C., until the reaction has ended. The reaction product is precipitated by adding a diluent, eg. methanol, ethanol, isopropanol, isobutanol or mixtures of methanol, isopropanol or ethanol with water, and is isolated by conventional methods.

The dyes of the formula I, where X is chlorine or bromine and n is 1 or 2 are obtained by halogenating the corresponding compounds of the formula I, where n is 0, in solvents which are inert under the reaction conditions, in the presence or absence of halogenation catalysts, by conventional methods.

Examples of suitable inert solvents are sulfuric acid, glacial acetic acid and, preferably, monohydrate (i.e., H 2 SO 4 .H 2 O). In addition, oleum containing up to 24% by weight of free sulfur trioxide, in the presence of boric acid, is a suitable inert reaction medium.

Bromine or chlorine are used as halogenating agents. The halogenation is advantageously carried out by dissolving or suspending the starting compound in the solvent and then adding the halogenating agent, eg. by passing it into the mixture, or adding it dropwise. The halogenation takes place at between 0° and 60° C., preferably at between 20° and 40° C. As a rule, the reaction has ended after from 2 to 15 hours. The dye is precipitated by pouring the reaction mixture on to ice or into an ice/water mixture and is isolated by conventional methods.

The amines Y-NH 2 required for the manufacture of the compounds of the formula (I) are obtained by reductive amination of 4-methyltetrahydropyranyl-3-aldehyde.

The new dyes are superior to the dyes described in British Pat. No. 1,284,932 in respect of their tinctorial and technological properties, eg. build-up capacity and stability to contact heat.

The dye obtainable as described in Example 2 is significantly superior to the dye disclosed in Example 38 of the above British patent, i.e. ##STR6## in its build-up capacity when dyeing polyester fibers, and in its heat stability (fastness to thermofixing), eg. when exposed to contact heat. If the fastness to thermofixing of dyeings of equal depth is tested at 210° C. (duration of 30 seconds), the dyeing produced using the dye of the invention (Example 2) bleeds only slightly on to the accompanying white polyester fabric. In contrast, the dyeing obtained with the dye (II) bleeds significantly into the accompanying white polyester material.

The Examples which follow illustrate the invention; parts and percentages are by weight.

200 parts of phenol, 8.8 parts of boric acid and 130 parts of toluene are heated for 3 hours at 130° C., and at the same time a toluene-water mixture is distilled off. The batch is then cooled to 80° C., 25.4 parts of 3-aminomethyl-4-methyl-tetrahydropyran and 30 parts of 1-amino-8-nitro-4,5-dihydroxyanthraquinone are added and the reaction mixture is stirred for 1 hour at 100° C. When it has cooled, the dye is precipitated by adding 300 parts of methanol, and is filtered off, washed with methanol and water and dried. Yield: 23.6 parts of dye (formula I, where n is 0 and Y is ##STR7## in the form of a dark powder, of melting point 221° C.

______________________________________

Analysis: C.sub.21 H.sub.21 N.sub.3 O.sub.6

______________________________________

Calculated: 61.3% 5.2% 10.2% 23.3%

Found: 61.5% 5.0% 9.9% 23.2%

______________________________________